1. The Field of the Invention
This invention relates to input devices for use with computing machines. More particularly, the present invention relates to computer input devices which are manipulated by the user's fingers or hand to generate a position signal which is used by the computing machine to control one or more variable parameters.
2. The Prior Art
Many different devices have been developed to allow a user to communicate with, and input information into, a computing machine. Such devices include keyboards, digitizers, light pens, joy sticks, track balls, and mice. The objective of all of these devices is to provide a more efficient alternative to the widely used QWERTY keyboard.
Exemplary of these alternative devices is a mouse. A typical mouse has a generally mound-like body which is grasped by a user and a cable exiting the body (which together resemble the body and tail of a mouse) which is connected to a computing machine. Most mice include a roller ball protruding from the underside of the mouse. The roller ball makes contact with and rolls upon a work surface on which the mouse is operated. A computer program, referred to as a "driver" or "driver program," resident in the computing machine converts the rotational movement of the roller ball into first and second electrical signals which are interactively represented on a computing machine display as movement of a cursor in both an X axis and a Y axis.
Mice are now available in various versions. "Tailless" mice are available which communicate with the computing machine without an interconnecting cable. Other varieties of mice do not include a roller ball but utilize an optical sensing mechanism to detect motion across an optical grid. While the mouse has become a popular alternative to a keyboard as a computing machine input device, it has several drawbacks.
Regardless of the type of mouse used, a mouse requires a significant amount of free work surface space. Moreover, another drawback encountered when using mice is that large movements of the user's arm or hand are necessary to position the device. For example, when using a mouse it may be necessary to roll the mouse a distance of one or two feet across the work surface to move the cursor between opposing corners of the display. If the resolution of the mouse, or any other input device, is reduced so that less dramatic movement is required, then it becomes increasingly difficult to precisely position the cursor using the device.
All the widely available alternative cursor positioning devices such as trackballs, joy sticks, and digitizers present one or more difficulties to a user trying to precisely position a cursor on a display. For example, the user must overcome the starting inertia of a mouse or a digitizer when moving to a new position. Furthermore, in the case of a mouse, a user might need to sweep his arm across a desk to roughly position the mouse and then have difficulty trying to precisely position the cursor even though fine motor movements of the hand and fingers are used to carefully finish the move.
In some applications in which alternative cursor positioning devices are used, the user must merely place the cursor in a general area of the display using the mouse. In other applications, such as in computer aided design (CAD), the cursor or other display element must be moved to precisely an exact position on the display. With some alternative cursor positioning devices such as mice or joy sticks, the positioning of the cursor at the exact location required can be a frustrating challenge to the user. Merely pushing the device in the required direction often results in overshoot. Moreover, the movement of a user's arm is seldom as controllable as the fine motor movements of a user's fingers. Thus, the previously available cursor positioning devices inherently present several drawbacks and all such drawbacks reduce the efficiency of a user's inputting information to a computing machine.
In view of the foregoing disadvantages and drawbacks, it would be an advance in the art to provide an input device for a computing machine which is more efficient, more accurate, and less tiresome to use than previously available input devices. It would also be an advance in the art to provide a computing machine input device which requires only a small amount of work surface to use and which can be used to interactively control a cursor position or other variable parameters controlled by computing machines. It would also be an advance in the art to provide a computing machine input device which can generate three position signals and which utilizes the fine motor movements of the user's fingers.